Having particles packed closely together but with no ordered structure, unlike amorphous solids, liquids will flow freely and not hold a shape (on their own). This state of matter has a constant volume and will conform to the shape of its containers. Examples include water, milk and juice.

Matter in this state has no structured arrangement and like a liquid, will take the shape of its container, but unlike a liquid, will also expand to fill it. The particles in a gas are loosely packed, and thus a gas can be compressed. Examples of gases include air and oxygen.

Plasma

Like gas, plasma has neither a set structure nor a definite volume; however, unlike gas, plasma molecules are electrically charged. Therefore, plasmas can produce magnetic electrical currents and magnetic fields, as well as conduct electricity. Examples of plasmas include lightning and the Earth's ionosphere.

Behaves like crystal and liquid states of matter, exhibiting order over large distances and disorder over small distances. Like crystals, these states greatly suppress variations in the density of particles . . . across large spatial distances so that the arrangement is highly uniform. At the same time . . . [these] systems are similar to liquids in that they have the same physical properties in all directions.

Four single cones, which support tetrachromatic color vision [seeing more wavelengths and maybe even colors than humans] and a double cone, which is thought to mediate achromatic [no color] motion perception.

Because of their different sizes and composition, the five cones in chickens' eyes (one each for green, blue, red and violet, as well as the cone that detects "luminance") cannot exist in an optimum orderly arrangement or array. Rather, their distribution appears irregular, although not random:

The individual cone patterns in the bird's retina are arranged such that cones of one type almost never occur in the near vicinity of other cones of the same type. In this way, the bird achieves a much more uniform arrangement of each of the cone types than would exist in a random (Poisson) pattern of points.

A remarkable type of correlated disorder at large length scales known as hyperuniformity . . . [where] the photoreceptor [cones] patterns of both the total population [all cone types] and the individual cell types [violet, red, blue, green and luminance] are simultaneously hyperuniform, which we term multihyperuniformity . . . .

The study's authors concluded that, given the variation in the cones, this pattern makes the best of a bad situation:

Because the cones are of different sizes it is not easy for the system to go into a crystal or ordered state. The system is frustrated from finding what might be the optimal solution . . . the typical ordered arrangement. While the pattern must be disordered, it must be as uniform as possible. Thus disordered hyperuniformity is an excellent solution.